Vehicles having more than one wheel often include a suspension system to aid in regulating the vehicle's ride and handling. Generally, the suspension system may include a control arm, which may connect a wheel assembly to the frame of a car. The length of a control arm may vary from one type or make of vehicle to another. The length of the control arm may also vary depending on the desired ride and handling characteristics. The length of a control arm may determine the angle of the wheel in relation to a road surface, for example camber, caster, or toe.
Camber angle is a measure of how much a wheel or tire on a vehicle leans or tilts, either inward toward, or outward from, the vehicle, when viewed from the front or back. As such, the camber angle can be defined in different ways by measuring the relative positions of various components on a vehicle. Where a wheel is tilted such that the upper part of the wheel is closer to the vehicle, the camber is said to be negative. Where the top of the wheel is farther from the vehicle, the camber angle is said to be positive.
The caster angle is typically defined by the angle between a vertical line and a line drawn through upper and lower steering pivots, as viewed from either side of the vehicle. As such, the caster angle can be defined in different ways by measuring the relative positions of various components on a vehicle. For example, the caster angle can be defined as the angle between a vertical line and a caster reference line drawn either through an upper strut mount and a lower ball joint or through an upper ball joint and the lower ball joint.
The toe angle is typically defined by the angle between a horizontal line drawn down the centerline of the vehicle and a line drawn perpendicular to the center axis of the tire and wheel assembly as viewed from either above or below. As such the toe angle can be defined in different ways by measuring the relative positions of various components on a vehicle. Where the forward edge of the tire is closer to the mid-plane of the vehicle than the back edge, the toe angle is said to be positive. Where the forward edge is farther from the mid-plane, the toe angle is said to be negative.
Adjustment of the camber, caster, and toe angles may affect the handling characteristics of a vehicle. For example, camber may be altered to allow for differing cornering characteristics. In some cases, these angles, and therefore a vehicle's handling characteristics, may be adjusted by choosing control arms having different lengths. In addition, when replacing damaged, worn out, or factory installed control arms with new control arms, the new control arm may have a slightly different length making the installation difficult. Changing of control arms on a vehicle often requires difficult and time consuming adjustments. Thus, a vehicle owner may choose to forego altering driving characteristics to avoid the expense and difficulty of swapping control arms.
What is needed is an adjustment mechanism that allows a vehicle owner or mechanic to alter control arm length to fit different vehicles and/or to easily alter the handling and ride characteristics of a vehicle without the need to remove or exchange a control arm.
The inventive adjustable control arm presented here provides for adjustment of control arm length with a cam structure, which may avoid the need to disassemble the wheel assembly and/or remove the control arm from the vehicle.